Chemisorption on metal surfaces

Abstract

Presents a coherent summary of the current understanding of chemisorption phenomena, stressing theoretical concepts and developments rather than experimental techniques. The rapid experimental development of surface science requires a more systematic approach to the explosion of chemisorption data. To this end, the common characteristics of chemisorption systems are first reviewed before the differences are discussed and trends identified, in a search for physical concepts that can systematise the observational data and perhaps make it possible to predict the behaviour of systems that have not yet been studied. The major topics discussed are the adiabatic potential energy surface, the electronic structure problem, the Newns-Anderson model, atomic and molecular chemisorption, and reactions and heterogeneous catalysis. A comprehensive review of experimental results is not attempted within the concept-oriented approach of this study. It is shown that simple models are able to describe semi-quantitatively the chemisorption bond for simple gas atoms, and that there is some understanding of the surface and adsorbate parameters that determine important experimental observables such as the chemisorption energy, bond lengths, and vibrational frequencies. For molecular chemisorption and the dissociation of molecules on metal surfaces the understanding is less well developed, but there is some qualitative understanding of a number of trends.